How to have c# call into native libraries on both Android & iOS?

I have a common c++ codebase that I have created wrappers in Java(via JNI) for Android, Objective C for iOS and c# for.NET(using PInvoke) to talk to the c++ code and these wrappers expose APIs for somebody else to consume. I am currently trying to think of a way to get rid of the Java and Objective C wrappers and only keep c#, by doing those I will have less wrapper code. I am wondering if there is some way in .NET to call into those platform specific native libraries for Android and iOS from C#?