The government's clampdown on tax dodgers is 'on track' to raise £4bn in 2012, says chief secretary to the Treasury Danny Alexander (pictured), although this is lower than the £5.3bn raised in 2010/11.

Speaking at the Liberal Democrat autumn conference in Brighton, he has vowed to raise a total of £9bn tackling tax avoidance by 2015.

He said he would ensure the number of staff employed to track down and prosecute tax evasion in Liechtenstein would double to ensnare those with illicit funds in offshore tax havens.

Alexander said that he plans to double the size of the HMRC team working on the Liechtenstein Disclosure Facility (LDF), as part of a further push in the fight against offshore tax evasion.

HMRC has confirmed that the existing dedicated LDF team will double to around 50 staff. This figure reflects the very specialist work of the team, and the relatively low target audience they are after.

An HMRC spokesman said: 'The LDF team is being doubled to around 50. The resourcing of this very specialist team is specifically designed to effectively target this individual customer group.'

Alexander's latest pronouncements were made two years after he coughed up an additional £900m for HMRC as part of a concerted drive to net tax dodgers both at home and abroad.

Alexander told the BBC: 'Fair taxes in tough times means everyone playing by the same rule book, and everyone paying their fair share,' he will say.

'We have this message to the small minority of wealthy people who don't play by the rules.

'We are coming to get you and you will pay your fair share.'

LDF has been an effective tool for tackling tax evasion since it was launched in 2009. It gives individuals with undisclosed income hidden in Liechtenstein until 2016 to come forward and pay tax without facing a hefty tax penalty. This clampdown alone is expected to deliver £3bn to the Treasury - three times the initial estimate.

Since 2009, those with secret bank accounts have been given the opportunity to voluntarily reveal details of their funds for a trade-off of a 10% capped penalty of the amount of tax evaded over the last decade.