Holyrood's powerful committees are the focus of the first power struggle between parties at the Scottish Parliament, with the SNP hard-pressed to staff them all.

Alex Salmond's administration is liable to repeated ambushes as none of them will have an SNP majority. His party managers are understood to want a cut in the number of committees, but opposition parties see the opportunity to use their combined clout to stretch Nationalist resources.

If they combine, the opposition can force a committee structure on the SNP. But Labour leader Jack McConnell yesterday sent a warning shot that the SNP should not try to undermine committees as a "central and vital" part of the parliament. "This is no time to rip up structures that have delivered success," he told MSPs.

Committees are a vital and powerful part of Holyrood's business, scrutinising and amending legislation and carrying out inquiries. Over the past eight years, the Executive coalition has had a majority on all of them, with which to ensure its legislation is carried and to block unhelpful inquiries being pushed by opposition MSPs.

Now, the SNP administration has to ensure not only that it wins important votes in the chamber of the parliament, but also that it avoids its policy being derailed in the committee rooms. Each committee is expected to have a ratio of three SNP MSPs to three Labour, one LibDem and one Tory, though some could have two of the larger parties and one each from the smaller.

Green MSPs have been promised the convenership of one of the larger subject committees, as part of the deal they struck with Alex Salmond last week to vote for him as First Minister.

If there are 16 committees, as before the election, that will severely stretch the time and capacity of only 31 SNP backbench MSPs.

The vital committee has become finance, which scrutinises the annual Budget Bill. Without a guaranteed majority to carry out the wishes of executive ministers, that will become the battleground for opposition parties wanting to set alternative spending priorities.

It is essential the SNP takes the opportunity of appointing the finance convener over the next four years.

Such posts are handed out in accordance with the proportion of seats each party has, with the largest party having first choice of convenership, and Labour having second choice.

The decision on the number of committees is to be made in the Parliament Bureau, and is expected within the next fortnight.