Plaid Cymru leader Ieuan Wyn Jones has been campaigning alongside Caerphilly candidate Lindsay Whittle in the town.
The pair have called for the current business rates system to be scrapped and replaced by a system of taxation based on profit.
Mr Whittle, who is also leader of Caerphilly County Borough Council, took the Deputy First Minister to a local café.
He said: “We then went to the Twyn and by a strange coincidence the first person Ieuan spoke to was originally from North Wales. We also met lots of local people and Ieuan spoke to a few loyal shop owners who highlighted the business rates issue.”
Ieuan Wyn Jones said that in government, Plaid had succeeded to bring down business rates but that the current scheme, introduced by the Conservatives would never be fair.
As from October 1 this year, businesses with a rateable value of up to £6,000 will get 100% relief and businesses with rateable value of up to £12,000 will get tapered relief of between 100% and 50%.
Ieuan Wyn Jones said that successive London governments had choked the potential of small businesses.
He said: “In order for Wales to succeed, our home-grown businesses must succeed. Successive London governments have introduced policy after policy that has stifled the success of our small businesses.
“London Labour has failed to reverse the unfair business rates system imposed by the Tories when they were in government.
“The Plaid-driven Welsh Government is doing all it can to lessen the burden of business rates on small businesses. But fundamentally Plaid believes that the system is unfair and taxation should be calculated according to the profit a business makes.
“Unfortunately, as things stand this can only be changed at a Westminster level.
“In failing to stand up to big business and the banks, the London parties have failed to protect small local businesses. London Labour spent billions bailing out the big city banks and financiers and yet too many Welsh businesses are still unable to get the funding they need to flourish.
“Plaid is calling for a more strategic approach from the London government in order to allow our businesses to grow.
“We are calling for a special venture capital fund to provide our businesspeople with the funds they need to develop new ideas and to create sustainable jobs across Wales.
“Publicly owned banks must also be made to increase affordable lending to small businesses that are trying to take the initiative and expand.
“Broadband coverage and communications are vital considerations for any growing business. The government has to invest in order to create the working environment that companies want and need.”