Amendments likely to be tabled will oppose further spending cuts and the chancellor's approach to green economics

Liberal Democrat activists hope to target George Osborne by opposing further spending cuts, especially in welfare, as well as condemning his approach to green economics by tabling a series of amendments at the party's autumn conference in a fortnight.

They also aim to urge the party leadership to reiterate its support for a mansion tax and its opposition to any welfare reforms that smack of greater compulsion for claimants.

The amendments are being circulated by the Social Liberal Forum, and reveal a growing disillusionment with the coalition's economic strategy. Many of the amendments are aimed at setting parameters for the Whitehall wide spending review due next year which will cover departmental spending limits after the 2015 election.

The Lib Dem conference is the most democratic of the three major conferences, and although motions passed are not binding on the parliamentary party, they are influential.

In a sign that some activists want to see a shift in economic policy, one amendment calls on the party to "prioritise measures to boost demand through public and private investment, using all tools available to government, including the flexibility of its mandate over further spending cuts, beyond those already in place that would suppress confidence and demand yet further".

It also asserts that spending cuts allied to monetary policy have failed to address the depressed state of the economy, and the further deterioration of the public finances caused by it.

Another calls for a wealth tax "in its own right and not a trade-off for further self-defeating cuts in welfare spending".

In a sign of the escalating tensions within the coalition over green policies, Duncan Brack, a special adviser to the previous energy secretary Chris Huhne, calls on conference to "condemn the repeated attempts by the chancellor to inhibit growth in renewable energy, currently one of the UK's most successful industries".

His amendment also calls for "an expansion of the Green Investment Bank's scale and remit as fast as possible, including relaxing the restriction in its ability to borrow before public sector debt begins to fall".

Brack also calls for the scrapping of the planned 2014 review of the carbon budget demanded by Osborne claiming it creates uncertainty around low-carbon investment and infrastructure.

An emergency motion tabled by SLF activist Gareth Epps suggests claimants should be given a choice over work experience placements and be paid the equivalent of the minimum wage.

His motion comes in the wake of the controversy over whether some work experience schemes represent a form of cheap compulsory labour.

Epps's motion concurs with a recent high court judgment that mandatory work schemes are not a breach of human rights, but they do involve jobless people being made to work for less than the minimum wage.

The motion states that greater fairness would be achieved either by making the company offering the experience top up the claimant's benefits, or by limiting their hours to match the sum of their employment benefits.

It also calls for more to be done by the Department of Work and Pensions to clarify whether a scheme is mandatory and whether there is a realistic prospect of a job at the end of the placement.

Conference chooses which two emergency motions to debate through a ballot: even if this motion isn't picked, it shows that party members are uncomfortable with more aspects of the welfare agenda than simply cuts.

Nick Clegg, the party leader, remains secure in his role, but knows his relationship with his activists is likely to come under greater pressure in 18 months or so. In a Guardian interview last month he called for an emergency further contribution by the rich, but did not specify if he was seeking a wealth tax, a long standing party demand.

Clegg has appointed Ryan Coetzee, former chief executive of the South African Democratic Alliance, as his new director of strategy based in the Cabinet Office. He is credited with a major role in driving up support for the DA as the main opposition party to the ANC helping it to win 3m votes at the last election in 2009 from a tiny base a decade earlier.

Coetzee replaces Richard Reeves, the more cerebral policy figure who has gone to America as part of a family move. Coetzee, a member of the Liberal Democrats' sister party in South Africa, has most recently been the special adviser to the premier of the Western Cape and party leader Helen Zille.