Generally, If the government were to increase taxes the rates of tax evasion could increase.
However, it can be argued that it depends on what kind of taxes were raised. If taxes on income go up tax evasion could very well go up because people might try not to claim some or all of their income. However, if sales taxes goes up it most likely wont because people will not be able to evade paying this tax unless they just decide not to buy products.