Support for the Labor Party in the Senate has increased since Kevin Rudd’s ascendancy, according to a new Morgan Poll.

At the same time, there’s speculation in the House on the Hill that the Coalition could lose control of the Senate earlier rather than later.

In the March/April period, Morgan finds 45.5% of Australian electors said they would vote Labor “if a federal election for the Senate were being held today”. This compares with 39% in September/October 2006, 40% in November/December 2006 and 42% in January/February.

Support for the ALP during March/April was highest in South Australia — 47.5% — and lowest in the Western Australia — 41.5%.

Support for the Coalition in the Senate during March/April was 32.5%, down 3.5% from its January/February result of 36%. Support for the Greens is on 9.5%, the Democrats are polling 4%, Family First 2%, One Nation 1%, and other parties and independents 5.5%.

Morgan has done state-by-state breakdowns — and also made some brave predictions:

New South Wales: ALP 46.5%, LNP 31%, Greens 9.5%, Democrats 4%, CDP 2.5%; Family First 1%, One Nation 1%, Other 4.5%. If a half Senate election were to be held now, this would result in three NSW ALP senators, two LNP senators, and one position determined by the allocation of preferences, most probably from the Greens.

Victoria: ALP 46%, LNP 34%, Greens 11%, Democrats 3.5%, Family First 3%, One Nation 1%, Other 1.5%. This would result in three Victorian ALP senators, two LNP senators, and one position determined by the allocation of preferences, probably a Green.

Queensland: ALP 44.5%, Liberal 25%, Greens 7%, Nationals 6%, Democrats 4.5%, Pauline Hanson 4.5%, Family First 2.5%, One Nation 1.5%, Other 4.5%. This would result in three Queensland ALP senators, two Liberal senators, and another senator, most probably one from the National Party, the Greens or Pauline Hanson once preferences have been allocated.

South Australia: ALP 47.5%, LNP 31.5%, Democrats 6.5%, Greens 5.5%, Family First 3.5%, One Nation 1%, Other 4.5%. This would result in three South Australian ALP senators, two LNP senators, and one position from the Greens, Democrats or Family First determined by the allocation of preferences.

Western Australia: ALP 41.5%, Liberal 36.5%, Greens 10%, Democrats 2.5%, Nationals 2.5%, CDP 2.5%, One Nation 1%, Family First 1.5%, Other 2.5%. This would most likely result in two or three Western Australian ALP senators, two LNP senators, one Greens senator, and possibly one position determined by the allocation of preferences.

Tasmania: ALP 44%, Liberal 29.5%, Greens 17%, Family First 2.5%, Other 7%. This would result in three Tasmanian ALP Senators, two LNP senators, and one Greens senator.

It’s hard to make accurate forecasts without knowing which way the preference deals will flow, and they won’t be finalised until after the close of nominations just before the election. However, there’s already been some interesting talk of the shape of the Senate after 1 July next year — and what it might mean for a Rudd Labor government.

It’s thought it could be unfriendly. That means PM Rudd might be tempted to call a double-dissolution poll not too far into the life of his government in the hope that a honeymoon period of popularity and the lower quota needed for election at a DD would produce a more favourable outcome for Labor.

There are risks with that approach, too. The lower quota could mean more minor party senators got up — and would the Senate block enough bills to give him the double-dissolution trigger to begin with?

And here’s one wildcard to leave you with. Sample sizes mean it doesn’t get covered in the Morgan poll, but watch the Senate race in the ACT. The two territories have two senators each. Rather than serving six-year terms, their terms shadow those of the House of Representatives.

It is just conceivable that the Greens could unseat ACT Liberal Gary Humphries. This would require an improbable swing of about 7%, but the Democrats almost managed the task in 1998.

If they pull it off, the Senate would be very different even before 1 July next year. The new state senators wouldn’t be sitting, but the new Territory senators would be there,  and the Coalition’s control of the upper house would be gone.