Single Party System
This is where only one party puts up candidates for election.
--> Effectively, all other parties are banned and there is no opposition.
EXAMPLE: A single party system dominated Germany in the 1930s and 1940s.
Two Party System
This has two major parties who each have a reasonable chance of gaining the majority seats in Parliament.
-->There may be other parties but they are unlikely to win any political power and may only seize a handful of seats.
EXAMPLE: It is argued that Britain, the US and countries such as New Zealand are typical examples of the system.
Dominant Party System
There may be a large number of parties that contest for each for seat but in reality, only one party has reasonable prospects of gaining power.
EXAMPLE: Japan in the 1950s to 1990s when the Liberal Democrats kept returning to power time after time.
Governments tend to be co-alitions of several parties because none has sufficient support to gain absolute power.
EXAMPLE: This system is particularly common in many European countries such as Italy and Belgium.