Scottish National Party candidate Annabelle Ewing is expected to decry government plans to introduce road tolls when she goes on a meet-the-people tour of Hamilton's shopping centres on Saturday - starting at Main Street, High Blantyre.
The would-be Westminster MP will be joined by the party's new MSPs for her whistle-stop visit.
The Labour Party, which is fielding candidate Bill Tynan, will set up a stall in Quarrie Street, Hamilton, as part of its campaign to win over voters for the election on 23 September.
Campaign in full swing
Liberal Democrat candidate Marilyne McLaren and Charles Ferguson, picked to stand for the Conservative party, are expected to keep a low profile over the weekend and begin campaigning in earnest on Monday.
The by election is being held to find a successor to the newly created peer, Lord George Robertson.
Labour's big guns were out in Hamilton on Friday - including UK Prime Minister and party leader Tony Blair and Scotland's First Minister Donald Dewar.
Mr Blair will remain in the country over the weekend where he will enjoy a stay as guest of the Queen at Blamoral.
He is expected to attend the traditional Braemar gathering on Saturday with the Royal family.
On his first day north of the border, Mr Blair was forced to defend the way the new Scottish Parliament is run.
'Proud Scots'
He said most Scots were proud of the parliament which he believed was a fair and modern form of government.
However, Mr Blair also acknowledged that the new seat of power had its critics.
The SNP has promised to highlight the cost of fuel in Scotland during their weekend of campaigning.
The party singled out Mr Blair in their attack on the cost of fuel - saying his journey from Hamilton to Balmoral would be prohibitively expensive for many Scots.
The Tories are focussing on Labour's record in the Scottish Parliament, saying the new executive has proved a flop.
And the Liberal Democrats are challenging Labour to expand public spending - while curbing the tax burden on the poorest in society.
Blair joins by-election campaign
(03 Sep 99 | Scotland)
Blair sparks by-election row
(24 Aug 99 | UK Politics)
Peerage ignites fierce election fight
(24 Aug 99 | Scotland)
Robertson becomes peer
(24 Aug 99 | UK Politics)
SNP seeks spirit of 1967
(04 Aug 99 | UK Politics)
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