Efforts to ease the transition between primary and secondary school are to be unveiled by Scotland's first minister.

Jack McConnell will outline his objectives during a keynote education speech on Tuesday.

He is also expected to announce other reforms designed to drive up standards in schools when he addresses head teachers from across Scotland.

Jack McConnell is speaking to head teachers

A Scottish Executive spokesman said research had shown that children making the move to secondary school can sometimes experience problems.

"On Tuesday the first minister will be setting out the first steps towards addressing what is a problem that has been around for as long as we can remember," he said.

New powers for head teachers to set their own priorities and greater use of specialist teachers for subjects such as music and sport are thought to be among the reforms to be announced at the event in Glasgow.

Mr McConnell is also expected to say that pupils should be encouraged to take part in more out-of-hours activities, such as breakfast and homework clubs, and that more vocational classes should be offered.

And he is expected to encourage more links with colleges and businesses.

'Biggest contribution'

Meanwhile, Education Minister Cathy Jamieson has refused to give her support to a campaign calling for further reductions in class sizes.

Scotland's biggest teaching union, the EIS, is calling for primary school class sizes to be reduced to 20 or less.

Scottish National Party education spokesman Mike Russell said this was the "biggest single contribution you can make" to boosting educational achievement.

I think we can actually be much more creative than simply reducing this to a matter of arithmeti

Cathy Jamieson Education Minister

"What Jack McConnell is doing and what Cathy is doing is rejecting all the ideas that are coming from south of the border, but they have no ideas of their own.

"But here is a really big idea that will make a huge difference," he told the BBC's Holyrood programme.

Ms Jamieson said teaching unions had welcomed initiatives to drive up the number of classroom assistants.

"We have to ensure we get more specialist teachers in," she said.

"We have to ensure we bring in other people with different skills and qualifications to support teachers.

"And I think we can actually be much more creative than simply reducing this to a matter of arithmetic."